Waterproofed fabric



' UNITED STATES PATENT OFFICE.

WILLIAM BEACH PRATT, OF WELLESLEY, MASSACHUSETTS, 'ASSIGNOR TO E. H.CLAPP RUBBER COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MASSA-CHUSETTS.

WATERPROOFED FABRIC.

Specification of Letters Patent.

Patented Aug. 17, 1920.

No Drawing. Application filed January 8, 1919, Serial No. 270,228.Renewed May 3. 1920. Serial No. 378,660.

To all whom it may concern:

Be it known that I, WILLIAM BEACH PRATT, a citizen of the United States,residing at Wellesley, in the county of Nor- 6 folk and State ofMassachusetts, have invented new and useful Improvements in WaterproofedFabrics, of which the followingris a specification.

, his invention has for its object the pro- 10 duction of a fabric whichis resistant to oxidation, capable of vulcanization onto rubber, andwaterproofed, so that it may be used for a great variety of purposes inthe art, such as in the manufacture of rubber tires, shoes, belting, hotwater bottles,

packing, rain-coats, filter cloth, carriage tops,-waterproof coverings,paulins, etc. i A fabric, embodying the present invention, consists of afibrous body or foundation treated with a non-colloidal sulfurterpenecompound, in which the fibers are saturated or impregnated with thecompound and thereby are rendered resistant to rotting or disintegrationwhen subjected to the elements. The fibrous body or foundation mayconsist of a thread, cord or rope, either single or interwoven orbraided with others in the form of a cloth or braid, or it may consistof a sheet or other fabricated form in which the fibers are interlockedor felted.

This foundation is treated withthe suitable sulfur-terpene compoundwhile the latter' is in a liquid state, that is, either when thinned bya, suitable solvent or rendered li uid by the application of heat.

he impregnating or converting compound should be non-c0lloidal so thatit will tend to penetrate the fibers of the founda- 40 tion, aswell ascoat them, and it should be of such oxidation-resistant character thatit will safeguard thefibers from rotting and disintegration, and willrender them water and weather proof. Furthermore such compound should beneutral, i. e.

neither acid nor alkaline, and should be capable of being united torubber and rubber compounds by vulcanization.

I have found that, by the digestion of certain terpenes (for example,oil of turpentine,) with sulfur in a reflux condenser under properthermal conditions, a neutral amorphous non-colloidal sulfur compound isproduced which may be employed in the production of a fabric embodyingthe present invention. In preparing such compound, oil of turpentine andsulfur, in the ratio of about 2 to 1.5 parts by weight, (or

if desired, in equal parts) are digested with pound, or the process ofproducing it.

When the reaction is carried to completion, the resulting product, 2'.e. the sulfur-terpene compound, is a hard tough black mass, breakingwith a conchoidal fracture, presenting a vitreous luster on the surfacesof the fracture. with reaction, partly soluble in acetone, sol; uble intoluol and in xylol, and insoluble in water.

der the heat of the hand, become so softened that it can be molded.

In the production of a fabric embodying the invention, I preferably dry,by the application of moderate heat, the fibrous foundation to eliminatemoisture therefrom (though this step is not essential), and then Ieither immerse the fabric in a bath of the liquid compound, or coat thelatter thereon. The sulfur-terpene compound is preferably thinned by asuitable solvent so that it will quickly penetrate the fibers and theinterstices between them, but under some circumstances I heat thecompound to a liquid or plastic condition and apply it as a paint. Fortreatin cloth, thread, felt or other fabrics, a satis actory solutionmay be prepared by dissolving 1 part by weight of sulfurterpene compoundin 4 parts by weight of xylol under mild heat. After the fabric has beenimpregnated therewith, the fabric is subjected to sufliciently elevatedtemperatures to drive ofl the solvent in a reasonable time, or, ifdesired, it is subjected to vacuum drying for more complete recovery ofthe solvent; according to common practice.

It is soluble in turpentine- A portion of this mass, when manipulatedbetween the fingers, will, un-' the fibers thereof,

One of the great advantages of a fabric impregnated with asulfur-terpene compound, as herein described, is that it possesses atensile strength that could not have been predicated on the strength ofthe original fiber. For example, a 17.5 ounce auto. fabric, such as iscommonly employed in the construction of pneumatic tires, when made fromshort staple American cotton, has been increased in strength, byimpregnation with said sulfur-terpene compound, to that of a similaruntreated fabric made of Egyptian cotton. Such fabrics produced fromhigher grades of American cotton, or of Egyptian cotton, when soimpregnated surpass in strength any similar untreated fabric made of anygrade of cotton whatever.

Likewise such fabrics or fabricated forms, as threads, sheets formed ofinterlocked threads (2'. e. woven, knitted or braided), paper or paperfelt, etc. when treated with the sulfur-terpene compound are increasedin strength to a marked degree.

Another of the great advantages of a material such as herein describedis that it will vulcanize onto and with rubber, and thus it may beemployed in the manufacture of all inds of rubber goods. For example, ifthe foundation consists of a woven fabric, treated as described, it maybe surfaced on 'one or both faces with a thin layer of rubber compoundand be used in the construction of hot water bags or fountain syringes,which will greatly outwear those as now commercially manufactured. Theprotection, which the compound affords to the fibers, prevents theirrotting and disintegrating when exposed to air, water, or weak acids oralkalis, and makes it possible to employ the material herein describedfor a great variety of uses.

It has heretofore been common practice, when a cord or sheet of fibrousmaterial is to be used with rubber compounds in the manufacture ofrubber articles, to friotion the same with a rubber coating in order topress the rubber into the interstices or meshes of the fibrous materialand permit the vulcanization of the fabric so frictioned with adjacentlayers or masses of rubber compound. The rubber, which is frictionedinto the fabric, does' not protect if the rubber coating is worn orseparates therefrom, and consequently the fibers are liable to rapidoxidasoak in or tion and disintegration. Moreover, the mechanicalmanipulations in the operation of frictioning rubber into fabric must.becarred out under most exacting conditions, for there is always a dangerof injuring the fibers and impairing the strength of the fabric, due tothe pressure requisite to press or mechanically force the rubber intothe meshes or interstices of the fabric.

A fabric embodying my invention has none of these disadvantages, for thesulfurterpene compound, being non-colloidal, will penetrate the fibersand become absorbed without mechanical pressure, and the strength of thefabric is greatly increased, as hereinafter pointed out. Each fiber maybe coated with a film of the compound which is capable of vulcanizationto rubber, and a greater contact between the rubber and the fabric istherefore afforded than is possible with friction cloth or fabric.

I do not claim herein either the herein described sulfur-terpenecompound, or the process of making the same, since they form thesubject-matter of my co-pending application Serial No. 328,235, filedOctober 3, 1919.

Having thus explained the nature of my said invention, and described away of making and using the same, although without attempting to setforth all of the forms in which it may be made or all of the modes ofits use, what I claim is 1. A fabric consisting of a fibrous foundationimpregnated with a non-colloidal sulfur-terpene compound.

2. A fabric consisting of a fibrous thread impregnated with anon-colloidal sulfur-terpene compound.

3. A fabric consisting of a plurality of interlocked threads impregnatedwith a noncolloidal sulfur-terpene compound.

4:- The herein described process which consists in permeating the fibersof a fibrous material with a non-colloidal sulfur-terpene compound.

5. The herein described process which consists in impregnating thefibers of a fibrous material with a solution containing a noncolloidalsulfur-turpene compound, and then removing the solvent.

In testimony whereof I have afiixed' my signature.

WILLIAM BEACH PRATT.

